Scientific Name:

Mandrillus leucophaeus

Conservation Status:

Where to see them:
Monkeys of Makokou, Ford African Rain Forest

Fun Facts:

Drills use many facial expressions to communicate with each other. One is a “grin” where they show their teeth (almost in a smile). Unlike most other primates, this is a friendly gesture (but can signal the animal is tense).

Male drills become very colorful as they mature. They develop red chins and red, pink and blue bottoms. These colors intensify when the male is excited.

The drill’s entire world range is smaller than the state of West Virginia.

 Drill Monkey

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Males weigh an average of 75 pounds; females weigh an average of 30 pounds.  

Drills are found in the countries of Cameroon and Nigeria and on the island of Bioko, Equatorial Guinea.

Mature primary forests

Drills live in large social groups (as many as 20 individuals) with many dominant adult males (but only one leader).  These groups can merge with other groups, creating large groups of over 200 individuals. Besides facial expressions, drills also utilize a wide range of vocal, olfactory, visual and tactile forms of communication to keep their group together, as well as to keep other groups away. They mark their territory by rubbing their chests on trees. Drills are diurnal, so they are most active during the day.

Drills are mainly frugivores (eating primarily fruit), but will also eat insects and edible plants. In addition to those items, the Zoo’s drills also eat vegetables, lettuce and a dry food containing vital nutrients.

Life Cycle

Females reach sexual maturity at about 3 years old, while males are sexually mature at about 6 years old. Gestation is 179-182 days, and a drill female usually gives birth to a single offspring (there has been one documented case of twins). The offspring stays with its mother for 15-16 months until it is fully weaned. Males will usually disperse from their natal group to form new groups. The average life span is 28-30 years.

Some of My Neighbors (IN THE WILD)
Chimpanzees, olive pigeons, Rumpi mouse shrews, Preuss’s monkeys and African pygmy squirrels

Population Status & Threats
Drills are among Africa’s most endangered primates because their numbers have been declining in all known habitat areas for decades. The decline is due to illegal commercial hunting, habitat destruction and fragmentation, and human development. Unfortunately, fewer than 10,000 drills remain in the wild, and numbers may be as low as 4,000.  Drills are fully protected by law in Nigeria and Cameroon, and portions of their habitat are technically safeguarded as national parks.  However, little real protection from hunting exists for drills, even in so-called protected areas.

Zoo Atlanta Conservation Efforts
In 2008, through the Zoo Atlanta Conservation Endowment Fund, the Zoo was able to significantly help with a project (spearheaded by the Drill Ranch in Nigeria) that is reintroducing rehabilitated drills back to their natural habitat.